To avoid heavy Rinka damage, perform the Crystal Flash while backed against the left door or inside the open door frame. Lay the Power Bomb immediately after destroying the Rinka with the closer spawn location.

Requires:

{
  "or": [
    {
      "resetRoom": {
        "nodes": [
          1
        ],
        "mustStayPut": false
      }
    },
    "Ice",
    {
      "obstaclesCleared": [
        "A"
      ]
    }
  ]
}
"h_canCrystalFlash"